This invention relates in general to electrical connectors and deals more particularly with an improved female connector or jack particularly adapted to receive a complimentary portion of a modular plug connector of FCC approved type. Such approved plugs are standardized by FCC regulation to assure mating engagement with associated jacks of approved type. However, FCC regulations allow some leeway in plug construction. Consequently, a nominal 6 pole plug for terminating a cable containing three pair of conductors will fit an eight pole jack, that is a jack particularly adapted to receive a nominal eight pole plug for terminating a cable containing four pair of conductors. Such plugs are usually provided with a row of fixed contacts as, for example, spade contacts, disposed within a row of contact receiving slots formed in the plugging end of the plug housing. Each fixed contact on such a plug is adapted to engage and deflect an associated spring contacts contained within a plug receiving cavity in jack housing.
Portions of the plug housing at laterally opposite ends of the row of plug receiving slots comprise solid plastic material, that is material free of slots. This arrangement presents no problem when the jack into which the plug is inserted contains the same number of contact as the plug or a lesser number of contacts. However, if a plug is inserted into a receptacle or jack having a larger number of spring contacts than the number of contacts carried by the plug, the outboard spring contacts, that is the spring contacts within the jack at opposite ends of the row, will be engaged by the solid material at laterally opposite ends of the plug housing and deflected a considerably greater amount than the other spring contacts therebetween which engage associated fixed contacts on the plug in a conventional manner. Such excessive deflection caused by insertion of a mismated plug often results in the outboard spring contacts taking a permanent set, as for example, when a plug having three pairs of fixed contacts is inserted into a jack having four sets of spring contacts. When a proper plug is thereafter inserted into the jack the "set" spring contacts within the jack may establish poor electrical contact with associated fixed contacts on the plug or entirely fail to function.
When a jack of the aforedescribed type is to be used for field termination it may be provided with terminals of insulation displacement type. However, such terminals as are presently available are suitable for terminating conductors in only a relatively narrow range of gauges. An increase in the range of gauges for which a terminal of a given size may be used is usually accompanied by an increase in the tendency of the terminal to become overstressed or take a set when used to terminate conductors at the larger end of the range.
Accordingly, it is the general aim of the present invention to provide an improved modular jack for receiving approved FCC modular plugs having varying numbers of fixed contacts without risk of damage to the jack. A further general aim of the invention is to provide an improved insulation displacement terminal for use on electrical connectors and the like.